1. What is hydrogen peroxide and what is it used for?
The SCCP opinion states:
3.1.Chemical and Physical Specifications
22.214.171.124. Primary name and/or INCI name
Hydrogen peroxide, dihydrogen dioxide, hydrogen dioxide, hydrogen oxide, oxydol, peroxide.
126.96.36.199. Chemical names
188.8.131.52. Trade names and abbreviations
184.108.40.206. CAS / EINECS number
Hydrogen peroxide: CAS:7722-84-1
Carbamide peroxide: CAS:124-43-6
220.127.116.11. Structural formula
18.104.22.168. Empirical formula
Hydrogen peroxide: H2O2
Carbamide peroxide: CO(NH2)2 . H2O2
3.1.2. Physical form
Hydrogen peroxide: Colourless liquid
Carbamide peroxide: White crystals or crystal powder
3.1.3. Molecular weight
Hydrogen peroxide: Mol. weight 34.0
Carbamide peroxide: Mol. weight 94.1
3.1.4. Purity, composition and substance codes
Hydrogen peroxide: Hydrogen peroxide – water solutions. Commercially supplied as a 33-37% aqueous solution. Common stabilisers include phosphoric or other mineral acid (to keep the product acidic), pyrophosphate salts (complexing agents to inhibit metal-catalysed decomposition) and stannate (a colloid-forming inhibitor).
Commercial solutions contain low (<0.1%) levels of organic impurities (total organic carbon) and very low levels (<10 ppm) of inorganic impurities, with total heavy metals usually <2 ppm. Carbamide peroxide: Products containing minimum 97% of the hydrogen peroxide – Urea adducts are available.
3.1.5.Impurities / accompanying contaminants
3.1.7.Partition coefficient (Log Pow)
3.1.8.Additional physical and chemical specifications
Pure H2O2 (not commercially available in EU)
Density: 1.4425 g/cm3
Vapour pressure :3 hPa
Boiling point:not available
Vapour pressure : not available
3.2. Function and uses
Hydrogen peroxide is capable of undergoing numerous reactions (e.g., molecular additions, substitutions, oxidations and reductions). It is a strong oxidant and can form free radical by homolytic cleavage. Carbamide peroxide is an adduct of urea and hydrogen peroxide which on contact with water break down to urea and hydrogen peroxide. For example, a 10% carbamide peroxide gel would yield a maximum of 3.6% hydrogen peroxide. 750,000 tonnes hydrogen peroxide (calculated as 100% H2O2) were produced in Europe in 1995. About 300 tonnes of carbamide peroxide were used.
The main usage of hydrogen peroxide is in production of chemicals (approx. 40%), bleaching pulp and paper (approx. 30%) and bleaching textiles (approx. 20%). Small quantities are used in cosmetics. Hydrogen peroxide is used for hair bleaching and for oxidation in permanent hair dyes and in oral hygiene products such as mouth-rinses and dentifrices as well as in tooth bleaching products.